The U.S. government has put a $5 million bounty on the head of a former cartel kingpin who murdered a DEA agent after a Mexican court freed him on a technicality back in August, law enforcement officials said.

The massive reward was announced Tuesday after Rafael Caro-Quintero, 61, was let out of a Mexican prison in the state of Jalisco in a controversial move that shocked law enforcement officials on both sides of the border.

The former leader of the now defunct Guadalajara Cartel had served 28 years of a 40-year sentence for torturing and killing DEA agent Enrique “Kiki” Camarena back in 1985 before a Jalisco judge overturned his conviction. The appeals court decided that his original trial never should have been held in federal court, but rather should have happened in state court.

His disappearance has infuriated U.S. officials, who requested Caro-Quintero’s extradition days after he was set free, sources said.

“Caro-Quintero was the organizer and mastermind of this atrocious act and his unexpected release from a Mexican prison was shocking and disturbing to law enforcement professionals on both sides of the border,” DEA Administrator Michele M. Leonhart said in a statement announcing the bounty.

“The United States Government will utilize every tool available, including the State Department Narcotics Rewards Program, to bring Caro-Quintero to justice.”